Introduction to pteridology

General Characters of Pteridophytes for UG and PG classes.

1. Dr. SushamaRaj R. V.
Assistant Professor of Botany

2. Groupofhighercryptogams withvascular
system–VascularCryptogams
Namedas“Telomobionata”byTakhtajan
(1964)and
“Embryobionta”byCronquistetal.(1968).
According to Longman Illustrated
DictionaryofBotany,
AndrewSugden(1984)definedPteridophyte
as“amemberofthedivisionPteridophyta
whichincludesferns,clubmosses and
horntails”.

3. ThePenguinDictionaryofBotany,E.Tootill
(1984)gavethedefinitionas“adivision
containing allthenonseed-bearing
vascular plants with heteromorphic
alternationofgenerationandindependent
gametophyte”.
RecentlyMasahiroKato(2005),defined
theseplantsas“free-sporingvascularland
plantsthatevolutionarilylinkbryophytes
andseedplants”.

4. Photosynthetic sporophyte with
differentiatedplantbody.
AbsenceofXylemVessels.
Alternationofgeneration withhaplo-
diplontic(heteromorphic)lifecycle.
Gametophyte isindependentandreduced,
knownasprothallus.
Antheridiaandarchegoniaareservedas
maleandfemalesexorgans.
Homosporous orheterosporous.
GENERAL CHARACTERS

5. Sporophytewithwelldifferentiatedroot,
stemandleaves.
Adventitious roots.Primary rootsare
ephemeral.
Stem,leavesandrootsaredevelopedfrom
asingleapicalcellwhich may be
one/two/threesided.
Leavesmaybesimple,smallandsessile–
Microphylls(Selaginelle,Lycopodiumetc.)
orverylargeandpetiolate–Megaphyllsas
inFilicinae.
PLANT BODY

6. Presence ofCircinatevernation.Leaf
trace,ifpresentisunbranched orshows
dichotomousbranching.
According toMehra andSoni(1983),
Stomatal pattern may be of
Psilophytaceous, Equisetaceous,
MarattiaaceousorFilicinenan.
Psilophytaceous patternwasthebasic
pattern.
Sporophyll–Sporangiabearingleaves.
PLANT BODY

7. Recent authors divided leaves of
Pteridophytesintothree
Trophophyll:-Leavesdoesnotproduce
spores.
Sporophyll:-Leafthatproducespores.
Brophophyll :-Aleafthatproduces
abnormallylargeamountofspores.
LEAVES

8. Welldeveloped vascularsystem with
XylemandPhloem.
Absenceofcambium.
Sporne(1975)reportedaboutthepresence
ofvascular cambium andseconday
thickening.
Stelemayvaryfromprotosteleato
dictyostele.
VASCULAR SYSTEM

9. Sporesareformedinsporangia.
May behomosporous (Equisetum)or
heterosporous(Selaginella).
Inhomosporous members, exosporic
gametophytes areseen.
Inheterosporous conditionisconnected
withendosporicpattern.
Heterospory istheuniqueevolutionary
featureofPteridophytes.
SPORANGIA

10. PresenceofStrobiliorcones.
InAzolla,Marsileaetc.specialbodies
namedassporocarpisseen.
According toBower (1935),each
sporangium containseither64orless
spores.
InIsoetes,grestestsporeoutputoccurs.
i.e.150,000to1,000,000sporesmay
developinasinglemicrosporangium
(Foster&Gifford,1959)
SPORANGIA

11. Sporesareseeninwell-organisedgroups
calledsori(Sorus).
Sorusinwhichallthesporangiamatureat
sametimeiscalledSimplesorus.
Sorusinwhichthecentreisoccupiedby
theoldestsporangiumandthesuccessive
youngersporangiapresenttowardsthe
baseiscalledGradateSorus.
Soruswithdifferentagesofsporangiais
calledmixedSorus.
SORUS

12. Sporegerminatesintoprothallus.
Green,simple,somewhat branchedaerial
structures.
Generallyhomosporous Pteridophytesare
monoecious andprotandrous.Equisetumis
protogynous.
Embedded archgonium.
PROTHALLUS

13. Antheridiummayembedded oremergent.
Antheridium iswithjacketandmany
antherozoids.
Archegonium withventerandneck.
Usuallyoneventercanalcellandegg.In
Lycopodium,thereismanyventercanal
cell.
PROTHALLUS

14. Zygoteisthefirstcellofsporophytic
generation.
Watermediated.
Chemotrophic movement.
Presenceoforganicacidssuchasmalic
andfumaricacid.
Yamanouchi (1908)andMasuyama (1972)
contributedinthestudyofpteridophytes.
FERTILIZATION

15. FERTILIZATION
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